Firebox for water for camping

ABSTRACT

A portable heating device includes an enclosed structure for containing and heating water. The firebox is constructed of steel and sits on four removable legs, allowing a campfire to burn on top of and underneath the firebox, maximizing heating elements. The heating of large quantities of water can be achieved by circulating water from a reservoir, through heat resistant hoses to the firebox, and then back into the reservoir once heated. This feature allows a hot tub for camping. A receptacle is placed in the upper firebox allowing a support post to be inserted, which supports a swivel arm or swivel grill for meal preparation. With the attachment of a steam diffuser, the portable heater can be used in combination with a sealable tent to become a sweat lodge. The device is also self-contained and easily transported by its conversion into a carrying case when not in use.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to fireboxes, especially portable ones. More specifically, this invention relates to portable fireboxes capable of heating large quantities of water for use in outdoor environments.

2. Description of the Related Art

It is often desired in outdoor environments to be able to heat a large quantity of water for use in bathing or other activities. Vitkay, U.S. Pat. No. 3,192,916, describes a portable hot water heater that includes a lightweight metal water tank or container, a heating element spaced from the tank, and a pair of hoses connecting the tank to the heating element. The tank includes structural features suited to form a carryall or knapsack for use on hiking or camping trips.

Nelson, U.S. Pat. No. 3,431,565, describes a portable shower that includes a collapsible shower frame with curtain, a reservoir for water, a pump connected to the water reservoir via suction tubing or pipe, and a battery to operate the pump. Adjustment can be made between hot and cold running water.

Evans et al., U.S. Pat. No. 4,455,997, describes a heating unit for hot tubs and/or spa units that is a submerged heating unit fueled by wood and/or coal. The unit is composed of a single shell of highly heat-conductive metal and is entirely submerged in the tank of water except for air and fuel inlets, and an exhaust outlet.

Pritchett, U.S. Pat. No. 5,203,316, describes a portable camp stove that may be placed over a fire in a pit in the earth, or the stove may completely contain a fire within it when its bottom plate and legs are attached. Other accessories of the stove include a stovepipe and oven combination, a water heating system, and a grill and rotisserie.

Thomas et al., U.S. Pat. No. 5,417,201, describes a portable water heating system, in which water is heated by an open campfire flame in an enclosed heat exchanger, and is circulated between the heat exchanger and a portable non-pressurized reservoir by thermosyphon action.

Englehart et al., U.S. Pat. No. 5,460,161, describes a campfire water heating apparatus and method, in which water is drawn from a first kettle through a supply hose to a heat exchanger placed in the campfire. The water boils inside the heat exchanger and discharges upwardly through a delivery tube to a collecting kettle.

Atwood, U.S. Pat. No. 5,937,768, describes a portable multi-purpose outdoor fire container and hot water storage system, in which a water flow system consists of a first input pipe and a second output pipe, each pipe connected between a hot water storage container and a cylindrical open-top container capable of supporting firewood on the bottom surface for heating water.

Seiber, U.S. Pat. No. 6,098,214, describes a device for wilderness plumbing in which a portable water heating system, adjustable in temperature, consists of two dual-use waterproof bags, two water lines, a heater core and a shower head.

Wehrly et al., U.S. Pat. No. 6,302,094, describes an indoor/outdoor heating and cooling system, consisting of a heat exchanging coil that is immersed in water in a heating pod heated over a fire or other heat source. Flexible tubing connected to the coil transmits heated water or other fluid under pressure from a water pump in a reservoir connected to the tubing. Loops of the tubing pass through various items used in outdoor activity including sleeping bags, tents, heaters, bowls, chairs, or a shower.

Hardee, U.S. Pat. No. 6,354,511, describes a portable system for heating water, in which the apparatus is self-contained such that additional sources of fuel or electrical power are not required, and can be used to provide heated water for showers, cleaning, food preparation, and the like.

Bilodeau, U.S. Pat. No. 6,880,547, describes a wood burning swimming pool heater, consisting of an oven for burning logs and branches, and a cylindrical chamber in which water circulates and heat is exchanged. Wood that can be found around an outdoor area is used as the fuel for this water heater.

The present invention is directed toward an improved capacity to heat water for use in outdoor environments, and has the added feature of being functional in cooking food. A primary objective of the present invention is to provide a closed loop circulation system, in which only one water-collection basin is required to serve as both the supply reservoir and the deposit reservoir.

Another objective of the present invention is to provide a campfire heating device that is both fire-supporting and self-supporting, which means that the firebox is one unit that supports both its water circulating structure and its campfire structure.

Another objective of the present invention is to provide a simple, portable, and self-containing device in which the unit itself becomes the carrying case used in transportation of the device.

Another objective of the present invention is to provide a portable device capable of producing a high volume of hot water in a relatively short period of time.

Another objective of the present invention is to provide optimum heating of the water inside the device by utilizing multiple heating surfaces.

One more objective of the present invention is to provide a heating device that complies with the U.S. Forest Service requirements for proper containment of a campfire, including requirements for wilderness areas.

SUMMARY OF THE INVENTION

The present invention provides a portable heating device with the ability to create a large volume of hot water in an outdoor setting. The firebox is preferably constructed of steel and sits on four removable legs, allowing a campfire to burn on top of the firebox, and below under the firebox, thus allowing the firebox to heat the water from top and bottom, greatly increasing the amount of heat that can be transferred to the water. The firebox has a double bottom that forms a closed vessel which serves as a water jacket, and water is circulated through this water jacket from a full tub of water until it reaches the desired temperature. In another embodiment of the invention, multiple hollow tubes, that are open at both ends, are vertically passed through the water jacket, whereby the tubes function as an additional heating element by allowing circulation of heated air from the flames below.

The present invention is self-contained and portable. In one embodiment, the components of the invention are able to be compacted and placed together on the topside of the firebox. The lower campfire piece then becomes a lid to close the top and latch to the upper firebox piece, thus creating a self-contained and easily transported carrying case.

The present invention may be utilized for a plurality of functions. In one arrangement, the present invention may be used with a portable tub, such as an inflatable tub, where the tub then serves as a hot tub for people to sit in while camping out. A 12 volt water pump, two high temperature rubber hoses, and a nearby source of enough water to fill the tub are required to use the present invention as a hot tub. Additionally, the hot tub could be adapted to a showering apparatus in which water is pulled from the hot tub reservoir to the showerhead for bathing. The present invention may also be arranged for use as a camp out sweat lodge. A small tent that can be zipped up with no ventilation, two high temperature rubber hoses, a bucket full of water, and a steam diffuser are required to operate the present invention as a sweat lodge.

A third function of the present invention, that may operate simultaneously with either of the above listed functions, is for use in food preparation. A vertical supporting post can be inserted into the top corner receptacle of the firebox and connected to either a swivel grill or swivel arm for hanging a cooking pot or Dutch oven.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is top perspective view of the portable heater according to one embodiment of the invention, functioning as a device for creating hot water for a hot tub.

FIG. 2 is a detail perspective view of the portable heater depicted in FIG. 1.

FIG. 3 is a side schematic view of the portable heater depicted in FIGS. 1 and 2.

FIG. 4 is a top, cross-sectional view of the portable heater depicted in FIG. 3.

FIG. 5 is a top, perspective, exploded view of the portable heater depicted in FIGS. 1-4.

FIG. 6 is a top, perspective view of some of the preferred equipment for operating the portable heater, according to the invention, including the firebox, battery, and amp/volt meter.

FIG. 7 is a top, perspective view of the reservoir for containing hot water, and the water pump, according to an embodiment of the invention.

FIG. 8 is a schematic, top perspective view of the portable heater functioning as a device for creating steam in a sweat lodge, according to another embodiment of the invention.

FIG. 9 is a side, detail view of a container of water connected to a funnel and valve for controlling the amount of steam for the embodiment depicted in FIG. 8.

FIG. 10 is a top, perspective, detail view of the steam diffuser for the embodiment depicted in FIG. 8.

FIG. 11 is a top, perspective view of an alternative embodiment of the portable heater, with swivel grill and fire placement.

FIG. 12 is a top, perspective view of the portable heater depicted in FIG. 11, but from the opposite direction and without fire placement.

FIG. 13 is a side view of the portable heater depicted in FIGS. 11 and 12.

FIG. 14 is a top view of the portable heater depicted in FIGS. 11-13.

FIG. 15 is a top, perspective, exploded view of the portable heater depicted in FIGS. 11-14.

FIG. 16 is a top, perspective view of the disassembled pieces for the portable heater depicted in FIGS. 11-15 arranged for storage or transport.

FIG. 17 is a top perspective view of the portable heater depicted in FIGS. 11-16 closed and secured for storage or transport.

FIG. 18 is a bottom perspective view of the portable heater depicted in FIG. 17.

DETAILED DESCRIPTION OF THE INVENTION

The above-described drawing figures describe the present invention, a portable heating device for heating large quantities of water in outdoor environments. The heating device is an enclosed structure, as seen in FIG. 1, with a sunken top panel (10) and resulting raised lip (12) for supporting a fire on top of the box. The bottom portion of the firebox (13) is preferably supported by four removable legs (14), as seen in FIG. 2, that are tall enough to build and sustain a fire (16) underneath the firebox in addition to the fire (16′) on top of the firebox. The firebox (13) and the legs (14) are preferably constructed of steel so as to withstand immersion into fire for the purpose of heating water within the firebox (13).

Two approximately 25-foot long high temperature hoses are connected to hollow steel posts (20) in the side of the firebox structure (13). A cross-section of the firebox (13) showing the hoses is provided in FIG. 4. Water is pumped into the firebox (13) through the inlet hose (17) in the side of the box (13), which is connected to a desired reservoir of water, and heated by the flames on the top and underneath side of the box (13). The water is then pumped back out of the firebox (13) through the outlet hose (18) in the same side of the box (13) as the inlet hose (17), which is connected to the desired reservoir of water. The firebox (13) has a double bottom, formed by the sunken top panel (10) and the bottom panel (22), as seen in the exploded view of FIG. 5. This double bottom forms a closed vessel serving as a water jacket, and water is circulated through this water jacket from a tub (24) of water, as seen in FIG. 7, until it reaches the desired temperature. This system represents a closed-loop circulating mechanism, in which the water circulates from a single tub or basin (24) only, and multiple basins for supplying the firebox invention and receiving from the firebox invention are not necessary. The water pumping action is achieved through the use of a 12V water pump (26), connected to a 12V deep cycle marine battery (28).

One alternate embodiment of the present invention is with several open hollow tubes (30) extending vertically through the water jacket, as seen in FIGS. 12-15. In this way, the invention optimizes heat exchange to the water by allowing hot air from the campfire (16) burning below the water jacket to circulate, in effect, through the water jacket.

The present invention is both self-supporting and fire-supporting. This means that the invention consists of one unit that acts to support the water heating device as well as the campfire structures that serve to heat the water within the device. A campfire (16′) can be built on the topside of the firebox (13), enclosed by the raised lip (12) that is formed by having a sunken top panel (10). A campfire (16) can also be built underneath the device and on top of the steel panel that serves as the lid (32), seen in FIG. 8, for the portable carrying case (FIG. 17) when the device is not in use. This lid (32) has a raised lip (12) when inverted to support a campfire (16), thus enclosing the campfire (16) underneath and preventing the fire from becoming out of control. This lower campfire lid piece (32) meets the U.S. Forest Service requirements for proper containment of a campfire (16).

The top side of the firebox (13) includes a receptacle (34) in one corner for receiving a vertical support post (36), best seen in FIG. 5. The vertical support post (36) can attach to a swivel grill (38) for the purpose of meal preparation. The vertical support post (36) can also attach to a swivel arm for the purpose of hanging a pot or Dutch oven during meal preparation. The swivel grill (38) and swivel arm can be raised or lowered to the desired height over the topside fire (16′) by loosening and tightening a bearing set screw (40) on the vertical support post (36). The swivel grill (38) and swivel arm can also swivel around to any position over the topside fire (16′). This feature of the present invention can be used simultaneously with either of the water heating arrangements to be discussed in the following paragraphs.

The present invention can be arranged to function as a water heating device for a portable camp-out hot tub (FIG. 7). An insulated portable tub (24), such as an inflatable tub, is used as the desired reservoir of water into and out of the firebox invention, and the two high temperature hoses are set up to run to and from the tub (24). A nearby source of water, such as a lake or stream, is necessary to fill the tub (24). Once the tub (24) is filled and connected to the firebox (13), water is pumped from the tub (24) into the water jacket through the inlet hose (17). The water inside the water jacket is then heated to the desired temperature by the campfires above and below the water jacket, and then once the water is heated, it is pumped out of the water jacket through the outlet hose (18), and back into the tub (24). This use of the present invention acts as a closed loop system, in which only one tub or basin for collecting water is required, thus eliminating the need for multiple supply and deposit reservoirs. The heat exchange rate for the present invention is approximately 41,500 BTUs per hour, which is enough to heat 250 gallons of water by 51 degrees in three hours, with an ambient air temperature below freezing.

The hot tub arrangement may also be connected to a showerhead apparatus for use in bathing or other cleaning. For this feature, the hot tub reservoir (24) is connected to a showering device by a heat-resistant hose, and then supplies firebox-heated water to a showerhead through the use of a pump.

The present invention can also be arranged to function as a water heating device for a portable camp-out sweat lodge, as seen in FIG. 8. A small tent (42) that can be zipped up with no ventilation is required, as well as a bucket of water (44) and a steam diffuser (46). The bucket of water (44) should be connected to the inlet hose (17) by use of a funnel. The inlet hose (17) is set up to run from the bucket of water (44), placed inside the tent (42), into the firebox (13). A valve (48) should be connected to the inlet hose (17) to control the flow of water to the firebox (13) and the rate of steam release. The outlet hose (18) is connected from the firebox (13) to the steam diffuser (46), placed inside the tent (42). The tent (42) is preferably placed above the firebox (13) on a slight hill, to allow for proper flow from the bucket (44) to the firebox (13).

The present invention is portable and forms a self-containing storage case (FIG. 17) when not in use as a water heating device. The legs (14), inlet and outlet pipes (20), vertical support post (36), swivel grill (38) and swivel arm are detachable and fit together on the topside of the box (13), as seen in FIG. 16. The underneath portion of the firebox, which contains the lower campfire (16), inverts to become the lid (32) for containing the device in one compact carrying case. The lid (32) latches to the top side of the firebox (13) and thus the present invention is self-containing, making transport of the device to an outdoor environment convenient and easy.

Although this invention has been described above with reference to particular means, materials and embodiments, it is to be understood that the invention is not limited to these disclosed particulars, but extends instead to all equivalents within the scope of the following claims. 

1. A portable heating device comprising an enclosed volume; wherein the volume has a top, sides, and a bottom; wherein the top surface of the volume is adapted with a raised lip to support a fire; wherein the bottom is supported above the ground by legs; wherein the enclosed volume has at least one inlet conduit and at least one outlet conduit for fluid.
 2. The heating device of claim 1 wherein the enclosed volume includes open hollow tubes extending vertically through the volume.
 3. The heating device of claim 1 wherein the top of the enclosed volume includes a receptacle for receiving a vertical support post.
 4. The heating device of claim 3 wherein the vertical support post is attached to a swivel grill.
 5. The heating device of claim 3 wherein the vertical support post is attached to a swivel arm.
 6. The heating device of claim 5 wherein the parts of the device fit together on the topside of the volume; and wherein a lid latches to the volume to create a self-contained carrying case.
 7. The heating device of claim 6 wherein the lid inverts to support a fire underneath the volume.
 8. The heating device of claim 2 wherein the top of the enclosed volume includes a receptacle for receiving a vertical support post.
 9. The heating device of claim 8 wherein the vertical support post is attached to a swivel grill.
 10. The heating device of claim 8 wherein the vertical support post is attached to a swivel arm.
 11. The heating device of claim 10 wherein the parts of the device fit together on the topside of the volume; and wherein a lid latches to the volume to create a self-contained carrying case.
 12. The heating device of claim 11 wherein the lid inverts to support a fire underneath the volume. 